Magnetic speaker



Dec. 27, 1938. w, J, PAREDES MAGNETIC SPEAKER Filed April '7, 1957 2 Sheets-Sheet l Dec. 27, 1938. W, J, PAREDES 2,141,820

MAGNETIC SPEAKER Filed April '7, 1937 2 Sheets-Sheet 2 Patented Dec. 27, 12938 lMAGNETIC SPEAKER Walter J. Paredes, Chicago, Ill., assignorto Arlavox Manufacturing of Illinois Company, a corporation Application April 7, 1937 serial No. 135.5%

5 Claims.

This invention relates to an improved magnetic speaker, and more particularly to the driving unit for the diaphragm thereof.

One feature of this invention is that it provides an improved speaker of the magnetic type; another feature of this invention is that the number 'of parts and the number 'of operations required are reduced; still another feature is that improved means arevprovided for adjusting the neutral position of the driving armature; yet another feature is a 'simplied mounting plate, eld assembly, and housing construction in the driving unit of the speaker; other features and advantages of this invention will be apparent from the following specification and the drawings, in whichz- Figure 1 is a side elevation of a speaker ernbodying this invention; Fig. 2 is a plan view of the same speaker; Fig. 3 is a vertical sectional view thereof; Fig. 4 is a transverse sectional view along the line 4'-4 of Fig. 3; and Fig. 5 is a view along the line 5.5 of Fig. 3.

The driving means for the diaphragm of a magnetic speaker must include .a permanently magnetized unitl of some kind to furnish a eld,

and a. motor unit comprising pole pieces, a field coilvvand generally a rockable armature. Present day competition in the field of table sets, automobile radios, and the like make it necess-ary to -turn out a speaker which retains desirable power,

sensitivity and fidelity characteristics and yet may be produced with a minimum of parts, waste metal, and assembly operations. The present invention provides an improved driving. portion for a magnetic .speaker'which achieves this object.

Where a rockable armature has a portion thereof extending outwardly between two pole pieces rather close-to each other, it is necessary to properly center .this armature after assembly ofthe speaker in order to insure the maximumv desired motion of the armature without striking either of .the pole pieces. The speaker disclosed herein achieves this object by the provision of an improved guide member adapted to vibrate with the armature, adjustable from without'the driv.

ing unit housing after the' complete speaker 'has been assembled.,

In the particular embodiment of this invention 'disclosed herein a basket or frame I0 of conventional type serves topcarry a diaphragm II here illustrated as a paper cone, although it may be of any other type. The frame also serves as a mounting for -thei'driving or vibratory assembly within the housing I2. 'The cone II is 'here shown as glued to the annular edge of the assembly (ci. ria-419) frame I0, and as having an annular washer I3' of cardboard or similar material on the other side thereof to.enab1e vibration of the cone'when the speaker frame is mounted on a/baiile-board or in.a cabinet. ,o

The driving assembly comprises a magnet unit I4; a' motor unit comprising two substantially LJ-shaped pole pieces I5 and I6', a field coil I l lying 'within the closure formed by these pole pieces, a rockable armature I8, and a pin I9 furnishing a: driving connection between the armature and the cone; a tensioning or guide means 2B adjustable by means of the stud 2|; top and bottom plates .22 and '23, respectively, and avsub stantially cylindrical housing member I2 of non:- magnetic material.

The magnet unit I4 ,consists here of a rectangular block of permanently magnetized material, preferably of the recently discovered nickel aluminum alloy type having very high magnetic strength per unit of cross-sectional area. `The top and bottom plates 22 and 23 and thel pole pole pieces to furnish a connection with the drivj ing pin i9, and isfmounted at the center 4by the two pins -24 and 25 to permit itA to rock about an axis passing throughthese pins. The spacers 26 provide a form or spool for the field 'coil -I1 and also. keep the pole .pieces separated the desired amount. The 'presence of an oscillating current in the field coil, furnished by the output of' a radio receiver, or the like, sets up corre--` spending electrical eilects in the armature which interact with the field between the pole piecesto cause the armatureto rock back and forth' and drive the. diaphragm II.v in mechanical oscillav tions which correspond .substantially to thecurrent input.

As will be noted tion of Fig. 3, the top and bottom plates 22 and 23 are pressed -or stamped to form shallow sockets 21,' 28, 29 and 30. Thesockets 2lv and 29 are particularly from considera.-

adapted to receive opposite ends 'of the magnet unit I 4 while the sockets 2li, and 30 similarly receive opposite ends or pole'pieces of the motor unit. The assembly is so madethat. the top and bottom plates are urged together to grippingly engage he opposite end s of the magnetand motor units, and to hold them in proper place therewithin solely by this frieticnal engagement.

l thereof with an annular flange 3l adapted to form a support on which the bottom plate 23 lies. The substantially cylindrical non-magnetic housing member I2 is provided with .an inwardly turned flange 32 adapted to engage the top plate 22 and lock the entire assembly together when the housing member i's fastened to the frame, as by the rivets 33. That is, the housing member I2 surrounds the two plates and prevents transverse movement, and the two annular anges 3| and 32 serve to hold these plates in gripping engagement with the magnet and motor units, in turn held from any undesired movement both by the frictional engagement and the fact that they are slightly sunk in the sockets in the plates. vA very simple assembly maybe followed, since it is only necessary to place the magnet unit andA motor unit in the proper recesses in one of the plates, place the other plate on the opposite ends thereof, place the housing member I2 around bothplates, and then lock the whole in place on the frame by the insertion and fastening of the rivets 33. l

An improved tensioning and locking means 20, heretofore mentioned, comprises a portion adapted to be fastened to the bottom plate 23, as by the screws 3l, an upwardly projecting portion 35 rising substantially vertically from the platey and a horizontal part substantially parallel to the plate comprising a base portion 38 and a flexible tongue member or portion 31. While the entire tensioning member is stamped out of a single piece of metal having the same gauge throughout, the base portion 33 is so much broader than the tongue 31 that the entire flexing or vibrating is done by this tongue. That is,

since this tongue is fastened to the driving pin I9, as by soldering, it vibrates therewith, but this vibration is not transmitted to the base member,

which remains practically stationary. The base member has the stud 2| threaded therein, this stud having the end of it bearing against the botfrom the bottom plate 23 may be varied by rota-v tion of the stud 2|, conveniently accessible from withoutthe housing. 'I'he tensioning member is so stamped that its internal spring tension urges the base portion toward the bottom plate member, it being held away from that member by the `interaction between the end of the stud and the f plate. 'I'hus the spacing of the base portion from the bottom plate may be varied by rotation ofthe stud, and this in turn acts through the flexible tongue 31 to move the armature .up or down,

against any resistance presentin its parts or the cone, to properly center it and have its neutral or inactive position equidistant from the pole The frame Il isprovided at the upper part pieces. The presence of the exible tongue, in addition to providing .convenient adjustment of the neutral position of the armature and driving pin, provides a` guide means preventing transverse vibration of the pin, and in other ways improving the quality of the output of the diaphragm.

While I have shown and described certain embodiments of my invention, it is to be understood that it is capable of many modifications. Changes, therefore, in the construction and arrangement may be made without departing from the. spirit and scope of the invention as disclosed in the appended claims, in which it is my intention to claim all novelty inherent in the invention as broadly as permissible, in view of the prior art.

Iclaim: t

1. A vibrator assemblyfor a magnetic speaker of the lcharacter described, including: a motor unit comprising pole pieces, a field coil, and a movable armature adapted to drive the diaphragm of said speaker; a magnet unit for energizing said pole pieces; and mounting means comprising a pair of plates of magnetic material having sockets formed therein for receiving said units and gripplngly engaging opposite sides thereof to furnish the sole support therefor.

2. A magnetic speaker of the character described, including: a frame; a diaphragm; a plate of magnetic material mounted on said i'rame; a motor unit comprising pole pieces, a field coil, and a movable armature for driving said diaphragm; 'a unit for energizing said pole pieces, comprising a blockoi permanently magnetized material; a second plate of magnetic material; and a housing member of non-magnetic material on said frame having a anged portion in engagement with said second plate, whereby said plates grippingly engage opposite sides ofsa'id units to furnish the sole support therefor.

3. Apparatus of the character claimed in claim 2, wherein said plates have sockets formed therein for receiving said units.

4. Apparatus of the character claimed in claim 2, wherein said plates are round and said housing member is substantially cylindrical and adapted to closely surround said plates.

5. A vibrator assembly for a magnetic speaker of the character described, including: a motor unit comprising pole pieces. a field coil, and a movable armature adapted to drive the diaphragm of said speaker; a magnet unit for energizing said pole pieces; and mounting means comprising a pair of plates for supporting said units solely by gripping engagement with opposite sides thereof, said plates being of magnetic material for completing the flux circuit between said pole pieces and magnet unit.

WALTER J. PAREDES.

for .transmitting the impulses determined by the projections on the periphery of the then effective cam.

3. A telegraph transmitter including a plurality of key levers, an operating shaft, a plurality of cams secured to said shaft each of said cams having its periphery formed with projections corresponding to the individual impulses representative of the character to which said cam is allocated, means operated by the key levers for rendering said cams individually effective, a start cam also secured to said shaft and arranged to be effective prior to said plurality of cams, and means operated by the cams identified with the respective characters and the start ca'm for transmitting impulses in accordance with the effectiveness of said cams.

4. A telegraph transmitter including a plurality of key levers, an operating shaft, a plurality of cams secured to said shaft each of said cams having its periphery formed with projections corresponding tothe individual impulses indicative of different characters, a universal bail, a start cam also secured to said shaft, a transmitting contact, and means operated by said bail through the operation of a key lever for rendering said start cam effective to effect through the operation of said contact the transmission of a start signal and thereafter one of said plurality of cams for the transmission of the character identifying impulses.

' 5. A telegraph transmitter including a plurality of key levers, an operating shaft, a plurality of character cams secured to said shaft each of said cams having its periphery formed with projections corresponding to the impulses individual to each character, a start cam also secured to said shaft, a transmitting contact, means common to the cams identified with the character and the start impulses, and means operated by said key levers for rendering said start cam and said character cams effective through said common means on said contact successively to effect vthe transmission of a start impulse followed by a series of character impulses.

6. A telegraph transmitter including a plurality of key levers, an operating shaft, a plurality of members carried by said shaft each of said members being identified with a particular character and arranged to control the transmission of impulses identified with the character allocated thereto, means for causing the transmission of a start impulse, means controlled by each of said key levers for rendering the member individual thereto effective for the transmission kof `impulses for the character thereof, and'means perated in timed relation with respect to said members for insuring that a stop impulse will be transmitted at the end of transmission of the character impulses regardless of the continued operation of the key lever through the operation of which the start impulse was transmitted.

7. AA telegraph transmitter including a plurality of key levers, a plurality of members, one for each character, impulses indicative of which are to be transmitted, a single transmitting contact, means operated by saidkey levers for rendering said members individually eifective on said contact, an additional set of contacts connected in circuit with said transmitting contact, and means operated upon the depression of any of said key levers for operating said additional contacts.

8. A telegraph system including a receiver comprising starting and printing mechanisms, and a transmitter including a plurality. of members one for each character, impulses indicative of which are to be transmitted, a plurality of key levers, means operated by said key levers for rendering said members individually effective, means common to said members and operated by each member for transmitting impulses in accordance with the operated member, means operative upon the depression of a key lever for transmitting a start impulse, and means effective in response to a start impulse for rendering said starting mechanism ineffective and said printing mechanism eective.

MAX DRESSLER. WILLY SKAWRAN.

Cir 

